|Author:||Gawaher, Muthanna ; Amin, M. S. M.|
|Book Group Author:||NA|
The purpose of this paper is to present a procedure to estimate the total irrigation water requirement for a command area of 2500 hectares in an and environment under various crops and soil types using GIS for data storage, analysis and visualization of results. Bani Al-Harith agricultural area in Sana'a basin, Yemen was chosen for the study. ArcView GIS was used to plan for suitable crops and estimate the irrigation water requirements based on the farmer's preference and soil types. Using the available soil maps, the soil characteristics such as salinity, texture and suitable crop types were overlaid to produce the crop blocks map. The water balance equation was used to produce the crop water requirement map considering the crop coefficient for different crop stages. The total water demand for each irrigation block was calculated by summing the three components, namely percolation loss through the soil, maximum evapotranspiration of the crop and leaching requirement (LR) to maintain an acceptable salinity level. The case study is an example of using GIS as an effective tool in irrigation planning. GIS facilities to acquire, store, analyse and display spatial data were used to produce the soil class map, soil profile map, crop map and water requirement map. The profile ECe values for the chosen crops is within the crop salinity tolerance for 100% yield except for blocks 4 and 5 where grape and coffee respectively are suggested to be grown. The profile ECe values are 18.37 dS/m in block 4 and 3.27 to 7.88 dS/m in block 5. The tolerance threshold of 100% yield for grape is 1.5 dS/m and for coffee is 3 to 6 dS/m. The salinity of the irrigation water was 2.08 dS/m. From the crop blocks map, the salinity tolerance level for 100% yield of onion for block 1 is 1.2 dS/m, tomato for block 2 is 2.5 dS/m, lucerne for block 3 is 2 dS/m, grape for block 4 is 1.5 dS/m, and the salinity tolerance level for 100% yield of coffee for block 5 is 5 dS/m. Leaching requirements were obtained by taking ECw value of 2.08 and ECe of 1.2, 2.5, 2, 1.5 and 5 for onion, tomato, lucerne, grape and coffee respectively. The peak total water requirement occurred in May and was found to be 5595 m3/ha, or 560 mm. The design irrigation water requirement for every block is shown in a map for easy visualization and manipulation to produce the best combination of soils, crops and water use. This methodology is useful for training irrigation engineers and water resource planners on the use of GIS technique to plan irrigation projects in arid areas.
|Pages:||347 - 361|
|Journal:||Management of Environmental Quality|
agricultural land, case studies, coffee, crop production,crop yield, evapotranspiration, geographical information systems,grapes, irrigation, irrigation requirements, irrigation water, leaching,lucerne, maps, onions, plant water relations, salinity, salt tolerance,soil texture, soil types, soil water balance, tomatoes, water use,Yemen, Allium, Allium cepa, Coffea, Lycopersicon esculentum, Medicago,Medicago sativa, Vitis, Vitis vinifera, Alliaceae, Liliaceae, Liliales,monocotyledons, angiosperms, Spermatophyta, plants, eukaryotes, Allium,Rubiaceae, Rubiales, Gentianales, dicotyledons, Lycopersicon,Solanaceae, Solanales, Papilionoideae, Fabaceae, Fabales, Medicago,Vitidaceae, Rhamnales, Vitis, West Asia, Asia, Middle East, LeastDeveloped Countries, Developing Countries, Threshold Countries, alfalfa,farmland, geographic information systems, GIS, Vitaceae, watering, SoilWater Management (Irrigation and Drainage) (JJ800) (Revised June 2002)[formerly Soil Water Management], Te